Device for returning oil separated from blow-by gases and accumulated in an accumulation chamber

ABSTRACT

The invention relates to a device for returning oil separated from blow-by gases and accumulated in an accumulation chamber ( 5 ) into the crankcase ( 2 ) of an internal combustion engine with a pump ( 9 ), wherein the pump ( 9 ) is located on a component ( 8 ) of the internal combustion engine, which component periodically changes the distance to the pump ( 9 ), and that the pump ( 9 ) can be driven by magnetic forces acting between the component ( 8 ) and the pump ( 9 ).

The invention relates to a device for returning oil separated fromblow-by gases and accumulated in an accumulation chamber into thecrankcase of an internal combustion engine with a pump.

A generic device is known for example from DE 41 01 203 A1. In thisdevice, an auxiliary pump is used for returning the separated oil. Theauxiliary pump can for example be a vacuum pump for generating lowpressure in a vehicle brake servo unit, which vacuum pump is driven bythe internal combustion engine. It is a disadvantage of this embodimentthat it necessitates a complex connection of the auxiliary pump to thedevice, in particular when the device is not located near the brakeservo unit.

A further device is known from DE 20 2004 004 802 U1, in which devicethe pump is driven by the vibrational energy generated during operationof the internal combustion engine. The generated vibrational energy isconditional on the motion of the piston. However, experience has shownthat the thus generated vibrational energy is not sufficient in internalcombustion engines comprising more than five cylinders and therebyinvolving an enhanced running smoothness.

It is an object of the invention to improve a generic device in such away that the return of the oil is rendered possible for internalcombustion engines comprising six and more cylinders as well, whereinthe constructional configuration shall be designed to be cost-effectiveand as simple as possible.

According to the invention, the object is solved by a device comprisingthe features of claim 1. Preferred embodiments can be learned from thesub claims.

According to claim 1, it is proposed that the pump is located on acomponent of the internal combustion engine, which componentperiodically changes the distance to the pump, and that the pump can bedriven by magnetic forces acting between the component and the pump. Thedevice proposed according to the invention thus provides the advantagethat an already present component of the internal combustion engine isused for driving the pump, and that the proposed drive by means ofmagnetic forces requires no additional components for transmitting theforce.

The magnetic forces can be easily generated by the pump or the componentbeing magnet-equipped and by the respective other component beingdesigned to be magnetic. The term “magnetic” here means that thecomponent is attracted or repelled by the respective other component. Inparticular all ferromagnetic materials or even plastic materialscontaining ferromagnetic particles lend themselves as magneticmaterials. Preferably permanent magnets lend themselves as magnets to beused, which permanent magnets do not require any connection to externalcomponents so that the whole device can be reliably operated inpermanent operation even in a hermetically sealed system.

A further preferred embodiment of the invention is that the pumpcomprises a vulcanised, bonded or insert-moulded permanent magnet, orthat the same is formed from a plastic material comprising magneticparticles and/or from an elastomer.

Thereby, a very easy way of magnet equipping is proposed, which canalready be carried out during the manufacturing process of the pump orof the magnet-equipped part of the pump. Furthermore, the magnet is thuslocated on the pump in a loss-proof manner so that the functionality isguaranteed even during permanent operation after a high number ofoperating hours. Using an elastomer lends itself inasmuch as themagnetic particles can already be introduced during the vulcanisationprocess and can be magnetised as needed.

Furthermore, the pump or the component can be formed from an elastomerand/or from a plastic material, which elastomer comprises the magneticparticles in a limited portion only. The limited portion thenexpediently is the portion having the smallest distance during theperiodic movement. As a result, optimal use is made of the generatedmagnetic force. The elastomer and/or the plastic material can then beinjected in two steps by injecting the elastomer and/or the plasticmaterial together with the magnetic particles in a first step, and byinjecting the plastic material and/or the elastomer without magneticparticles in a second step. Both materials then unite by beingvulcanised or fuse in the tool so that the finished part cansubsequently be taken out of the machine.

It is further proposed that the pump comprises a diaphragm, and that thediaphragm can be induced to perform a stroke movement as a result of thechanging distance of the component of the internal combustion engine.The proposed diaphragm provides a very easy but effective way oftransforming the movement of the component moving with a periodicallychanging distance into a pressure pulsation effecting the return of theoil.

The diaphragm preferably has a spring elastic configuration, wherein thesame can automatically be moved back to its initial position afterperforming the stroke movement. The diaphragm itself can for example bemade of an elastomer, wherein the diaphragm then summons up the requiredreset force for moving back to the initial position by itself by meansof its shaping. Alternatively, the diaphragm can also be mounted in aresilient manner and can consist of a dimensionally stable material,wherein the spring forces then pretension the diaphragm to the initialposition.

One possibility of shaping is that the diaphragm comprises acircumferential bead. By the proposed bead, a particularly large strokevolume is provided at an equal dimension of the diaphragm so that,conversely, for a predetermined stroke volume, the diaphragm can bereduced in size accordingly.

It is further proposed that the pump is assigned to an intermediatechamber, and that the intermediate chamber can be connected to theaccumulation chamber via a first non-return valve permeable in the inletdirection, and to the crankcase via a second non-return valve permeablein the outlet direction. By the proposed assignment of the pump to anintermediate chamber and by the connection to the accumulation chamberand to the crankcase via non-return valves, a device is provided, bywhich the movement of the periodically changing distance is transformedinto a continuous sequence of alternating oil intake phases from theaccumulation chamber and oil outlet phases into the crankcase.

A constructively easy way of transforming the periodic excitation by thecomponent of the internal combustion engine is that the pump, at a smalldistance to the component, generates low pressure in the intermediatechamber and thereby intakes oil from the accumulation chamber by meansof the first non-return valve into the intermediate chamber, and, at alarge distance, pumps the oil from the intermediate chamber into thecrankcase by means of the second non-return valve. The low pressurerequired for the pumping process is thus generated in the intermediatechamber by generating a magnetic attractive force by the component beingmoved by so that even in the event of the pump not functioning, as forexample at a decreasing magnetic force, a distance is present betweenthe pump and the component so that the component of the internalcombustion engine does not touch at the pump and the perfect movement ofthe component cannot further be disturbed.

For example the cam shaft, the gas exchange valves or parts of the levermechanism acting upon the gas exchange valves, as for example camfollowers, rocker arms, roller-type cam followers, lend themselves ascomponents moving with a periodically changing distance. These do notonly provide the advantage of already performing a periodic movement dueto their function, but also of being located geometrically near theplace where the oil separated from the blow-by gases is returned in thevalve body.

In particular in view of the functional reliability at a high number ofoperating hours it is proposed that the pump can be driven by thecomponent in a non-contact manner. This provides the advantage that noabrasion occurs, and that the parts cannot lock or disturb each other'smovement by touching at each other or by clamping.

In the following, the invention is described in more detail on the basisof preferred embodiments, wherein the figures show in detail:

FIG. 1: Device with a pump driven via a cam shaft

FIG. 2 a: Device according to FIG. 1 in the position “intaking oil fromthe accumulation chamber”

FIG. 2 b: Device according to FIG. 1 in the position “discharging oilinto the crankcase”

FIG. 3: Device with a pump driven via a lever acting upon a gas exchangevalve

FIG. 1 shows a device 1 for returning oil separated from blow-by gasesand accumulated in an accumulation chamber 5 into the crankcase 2 of aninternal combustion engine (not shown) with a pump 9. Herein, there isalways talk of accumulated and separated oil, but it is in fact a matterof a mixture of oil with parts of unburnt fuel and water. The operatingmode of the device in its basic principle, except the newly designeddrive of the pump 9, corresponds to DE 20 2004 004 802 U1 of the sameapplicant, which document thus explicitly is to be added to thedisclosure of the present application. The blow-by gases are introducedvia an intake line 3 and first are directed through an oil separator 4.The separated oil is accumulated in an accumulation chamber 5 comprisinga depression, on which a non-return valve 7 a spring-loaded in theclosing direction is located. When the spring force loading thenon-return valve 7 a is exceeded, the non-return valve 7 a opens andallows the oil to discharge into an intermediate chamber 6, from whichthe same again can be directed further on into a crankcase 2 via anon-return valve 7 b spring-loaded in the closing direction. Thepressure in the intermediate chamber 6 can be varied via a pump 9designed as a diaphragm, wherein the diaphragm 9 can be set into astroke movement by a component, here a cam shaft 8. The cam shaft 8,during its rotation, performs a movement periodically changing thedistance, by which movement the stroke movement of the diaphragm iseffected. For a better understanding of the invention, FIGS. 2 a and 2 bshow two different positions of the pump 9 driven by the cam shaft 8. InFIG. 2 a, the cam of the cam shaft 8 is located directly in front of thepump 9 designed as a diaphragm at a distance D1. The diaphragm 9 isequipped with a magnet 11 so that the same is attracted in the arrowdirection by the ferromagnetic cam of the cam shaft 8. As a result ofthe stroke of the diaphragm 9 low pressure symbolized by the symbols isgenerated in the intermediate chamber 6 causing the non-return valve 7 ato open and allowing a transportation of the oil from the accumulationchamber 5 to the intermediate chamber 6. In order to facilitate thestroke movement and to increase the stroke volume, respectively, at anequal diaphragm surface, the diaphragm 9 is provided with an elasticcircumferential bead 12. The diaphragm 9 itself can be formed forexample from an elastomer, into which a magnet 11 has been vulcanised orinserted by insert-moulding. Alternatively, the elastomer itself cancomprise magnetic particles as well, in particular in the area beinglocated directly opposite the cam of the cam shaft 8. The magnet 11 isthereby further protected against external influences like dirt,temperature or mechanical stress. In the position shown in FIG. 2 b, thecam shaft 8 is rotated by 90 degrees in the clockwise direction inrelation to the position shown in FIG. 2 a, whereby the distance betweenthe cam shaft 8 and the diaphragm 9 is increased up to the distance D2.Due to the increased distance D2 the magnetic force is lower so that thediaphragm 9 has performed a reset movement in the arrow direction. Inorder that the reset movement is reliably performed, and that thediaphragm 9 does not rest in the position shown in FIG. 2 a, thediaphragm 9 is spring-preloaded in the reset direction by the bead 12and/or by the choice of the material so that the same automaticallymoves back from the position shown in FIG. 2 a to the position shown inFIG. 2 b. Alternatively or additionally, the diaphragm 9 can however bespring-preloaded with spring elements as well for supporting the resetmovement. By the retraction movement of the diaphragm 9, the pressure inthe intermediate chamber again increases so that the non-return valve 7b then opens and the oil is directly or indirectly directed further oninto the crankcase 2.

FIG. 3 shows an alternative embodiment of the invention, in which thepump 9 is driven by a rocker arm 14. The rocker arm 14 with one endrests against a rotating cam shaft 8 and thereby performs a periodicswivelling motion so that the end of the rocker arm 14 resting againstthe valve 13 performs a movement with a periodically changing distancein front of the diaphragm 9. Apart from that, the transportation of theoil from the accumulation chamber 5 into the crankcase 2 is effectedidentically with the process described in FIGS. 2 a and 2 b.

Basically, it should be noted that, when the pump 9 is standing stilland the oil has been accumulated, the non-return valves 7 a and 7 b opendue to gravity and the oil can discharge so that even in the event of afailure of the pump 9 the oil is returned. The pressure pulsationgenerated by the pump 9 in the intermediate chamber 6 causes thenon-return valves 7 a and 7 b to alternately open and close so that theoil flow is returned independent of its volume. In the extreme case,when no oil is separated, the pump 9 consequently pumps air.

1. Device for returning oil separated from blow-by gases and accumulatedin an accumulation chamber into the crankcase of an internal combustionengine with a pump, wherein the pump is located a small distance from acomponent of the internal combustion engine, which componentperiodically changes the distance to the pump, and that the pump isdriven by magnetic forces acting between the component and the pump. 2.Device according to claim 1, wherein either the pump or the component ismagnet-equipped, and that the respective other part is designed to bemagnetic.
 3. Device according to claim 1, further comprising a permanentmagnet.
 4. Device according to claim 3, wherein the permanent magnet isselected from the group consisting of vulcanised, bonded orinsert-moulded.
 5. Device according to claim 1, further comprisingplastic material comprising magnetic particles.
 6. Device according toclaim 1, further comprising an elastomer comprising magnetic particles.7. Device according to claim 1, wherein the pump is formed from anelastomer, and magnetic particles are located within the elastomer. 8.Device according to claim 1, wherein the pump is formed from a plasticmaterial, and magnetic particles are located within the plasticmaterial.
 9. Device according to claim 1, wherein the component isformed from an elastomer, and magnetic particles are located within theelastomer.
 10. Device according to claim 1, wherein the component isformed from a plastic material, and magnetic particles are locatedwithin the plastic material.
 11. Device according to claim 1, whereinthe pump comprises a diaphragm that can be induced to perform a strokemovement as a result of the changing distance of the component of theinternal combustion engine.
 12. Device according to claim 11, whereinthe diaphragm has a spring configuration and can automatically be movedback to the initial position after performing the stroke movement. 13.Device according to claim 11, wherein the diaphragm comprises acircumferential bead.
 14. Device according to claim 1, wherein the pumpis assigned to an intermediate chamber, the intermediate chamber beingconnected to the accumulation chamber via a first non-return valvepermeable in the inlet direction, and to the crankcase via a secondnon-return valve permeable in the outlet direction.
 15. Device accordingto claim 14, wherein the pump, at a first distance to the component,generates low pressure in the intermediate chamber and thereby intakesoil from the accumulation chamber via the first non-return valve intothe intermediate chamber, and, at a second distance, pumps the oil fromthe intermediate chamber into the crankcase via the second non-returnvalve, the second distance being greater than the first distance. 16.Device according to claim 1, wherein the component is selected from agroup consisting of a cam shaft, one of the gas exchange valves or apart of the lever mechanism acting upon the gas exchange valve. 17.Device according to claim 1, wherein the pump can be driven by thecomponent in a non-contact manner.
 18. Device for returning oilseparated from blow-by gases and accumulated in an accumulation chamberinto the crankcase of an internal combustion engine with a pump, whereinthe pump is located a first distance from a component of the internalcombustion engine, which component periodically changes the distance tothe pump to a second distance, and that the pump is driven by magneticforces acting between the component and the pump.
 19. Device accordingto claim 18, wherein the second distance is greater than the firstdistance.
 20. Device for returning oil separated from blow-by gases andaccumulated in an accumulation chamber into the crankcase of an internalcombustion engine with a pump, wherein the pump comprises a diaphragmand the pump is located a first distance from a component of theinternal combustion engine, which component periodically changes thedistance to the pump to a second distance, the device further comprisinga permanent magnet positioned such that the pump is driven by magneticforces acting between the component and the pump.